Correcting Actions

How do you stop a kid from being a chucker?

I figure it's best fixed whilst a bowler is young rather than letting it slide - but technically does anyone have any experience of straightening arms and any ideas on the best aspects of an action on which to focus? I'm tending towards the front arm creating a fully extended position pre delivery to try eliminating the "extra effort" bend, but it's difficult to self regulate...

I had a kid in the U12s last year who had a suspect action and one of the other kids actually came up with an idea that went a long way to correcting the problem. Seems this little genius`s brother had been through some elbow surgery and had a brace that was hinged and had a protractor on the hinge that the physio used to limit the range of motion. With the idea being to slowly increase the amount of bend whilst the patient is recovering. He loaned it to his team mate to wear while he was practicing and with it limited to 10 degrees of bend he was able to cure his problem in just a few months.

My coach had one of our bowlers hold the ball with the ball facing the batsmen with the back of his hand facing down, opposed to having the back of the hand faing up and cocked. It appears to have worked to an extent.